This invention relates generally to pay-off constructions for use with wire-filled spools, and more particularly to devices of this type which employ both a wheel and a brush having radially extending tines adjacent the periphery of the wheel in order to control the movement of the strand as it is being de-reeled.
In particular, the invention relates to improvements in the wire take-off mechanisms illustrated in U.S. Pat. No. 3,972,489 dated Aug. 3, 1976, issued to Joseph J. Kovaleski, and entitled TENSION BRUSH WITH ADJUSTABLE BRAKE, and U.S. Pat. No. 4,298,174 dated Nov. 3, 1981, issued to Joseph J. Kovaleski, and entitled WIRE TAKE-OFF DEVICE.
U.S. Pat. No. 3,972,489 shows a take-off mechanism which employs a rotatable wheel and a fixedly-mounted tension brush carried on a shaft disposed at one of the spool ends. The wheel was provided with an adjustable brake which slowed its speed somewhat with respect to the orbital velocity of a strand of wire that was being payed off. This had several beneficial effects. One was that the small drag provided by the brake tended to minimize the inertia effect of the wheel under circumstances where the wire speed was suddenly reduced. Without the brake the wheel tended to keep turning, causing additional turns of wire to be de-reeled even though the take up movement may have suddenly stopped, or the speed been abruptly cut. Additionally, with a freely rotating wheel, under certain circumstances there was a tendency for the strand to engage a single point on the wheel such that the latter would move in synchronism with the strand. When this occurred, the strand eventually gouged a notch or recess in the wheel. The effect quickly worsened after the initial gouge was formed, since the strand often lodged at this one point.
In addition, with larger wire sizes and reels, there occurred excessive brush wear, necessitating frequent replacement. Under certain conditions, the wire could "balloon" out, that is, leave the brush. Such an occurrence meant that the strand was completely out of contact with the brush, and the desired control effect of the brush was thus lost.
U.S. Pat. No. 4,298,174 shows an arrangement for de-reeling the wire from two filled spools in succession, where a single continuous length of wire carried over from one to the second. In this patented device, the spools were provided with freely rotating wheels which turned under the action of the moving strand, and in addition, motor-powered brush drivers were provided, for imparting a predetermined rotation to the tension brush assemblies. This arrangement operated well from the standpoint of reducing the relative speed between the strand and the brush. It was, however, somewhat complex in its operation, since there was associated with the motor drives, control circuitry which was needed to sense wire speed and adjust brush speed accordingly in order to produce the desired relative movement between the brushes and the strands.